Wafer positioning pedestal for semiconductor processing

ABSTRACT

An assembly used in a process chamber for depositing a film on a wafer and including a pedestal extending from a central axis. An actuator is configured for controlling movement of the pedestal. A central shaft extends between the actuator and pedestal, the central shaft configured to move the pedestal along the central axis. A lift pad is configured to rest upon the pedestal and having a pad top surface configured to support a wafer placed thereon. A pad shaft extends between the actuator and the lift pad and controls movement of the lift pad. The pad shaft is positioned within the central shaft and is configured to separate the lift pad from the pedestal top surface by a process rotation displacement when the pedestal is in an upwards position. The pad shaft is configured to rotate relative to the pedestal top surface between first and second angular orientations.

CLAIM OF PRIORITY

This application is a divisional of and claims priority to U.S.application Ser. No. 15/291,549 filed on Oct. 12, 2016, entitled “WaferPositioning Pedestal for Semiconductor Processing,” which isincorporated herein by reference in its entirety.

TECHNICAL FIELD

The present embodiments relate to semiconductor substrate processingmethods and equipment tools, and more particularly, a wafer positioningpedestal for processing a wafer at different wafer to pedestalorientations.

BACKGROUND

Improved film uniformity is important in plasma-enhanced chemical vapordeposition (PECVD) and plasma atomic layer deposition (ALD)technologies. The chamber systems implementing PECVD and ALD areassociated with a hardware signature that contributes to nonuniform filmdeposition. For example, the hardware signature can be associated withchamber asymmetry and with pedestal asymmetry. Furthermore, manyprocesses experience azimuthal nonuniformity of various origins. Ascustomers push to locate die ever closer to the wafer edge, thenumerical contribution of this azimuthal nonuniformity to overallnonuniformity grows. Despite best efforts to minimize damage and/ornon-uniform deposition profiles, traditional PECVD and plasma ALDschemes still need improvement.

In particular, multi-station modules performing PECVD and ALD feature alarge, open reactor that may contribute to azimuthal nonuniformities(e.g., NU in the theta direction). For example, some nonuniformities mayresult in a characteristic film thickness tilt towards the spindletransfer mechanism in the center of the reactor. Nonuniformities alsoexist in single station modules, due to nonuniform physical chambergeometries including those caused by assembly and componentmanufacturing tolerances.

Traditionally, deposition nonuniformities have been compensated byphysically tilting the showerheads, such that the showerheads areintentionally oriented not parallel to the pedestals. Although notelegant solution, it has been historically effective. However, theeffectiveness of this scheme is growing ever more limited, especially asdie size decreases and edges of the wafer are increasingly being sourcedfor dies.

Processing the wafer in multiple orientations without rotating thehardware signature has been shown to be effective in filtering outazimuthal non-uniformity. The most basic current method in the prior artincludes partially processing the wafer, removing the wafer from theprocess chamber, rotating the wafer in a separate wafer handler, andthen reinserting the wafer for further processing in the neworientation. The main advantage of this method is no hardware inside thechamber is rotated. However, this prior art solution has disadvantagesof throughput, contamination, and significant extra hardware.

Another solution in the prior art rotates the whole pedestal duringprocessing. However, this solution has the adverse property of rotatingthe non-uniformity associated with the pedestal along with the wafer. Inthat case, the pedestal can have a non-uniformity signature that may notbe negated and may appear on the wafer during processing. Moreover, edgeeffects of the wafer in a pocket are another class of the non-uniformitythat is directly rotated with the wafer when the whole pedestal isrotated during processing. That is, non-uniformity is not appreciablyimproved with pedestal rotation (e.g., in ALD oxide deposition).Furthermore, in addition to limited performance, rotating the wholepedestal requires the expense of passing RF power through the rotatingpedestal. This requires a costly circuit for impedance matching througha slip ring to pass sufficient RF power to the plasma. Rotating thewhole pedestal also complicates the delivery of fluids and gases, usedfor cooling for instance. Additionally, heating systems present in thepedestal also requires rotation, adding to cost and complexity.

It is in this context that disclosures arise.

SUMMARY

The present embodiments relate to providing improved film uniformityduring PECVD and ALD processes in single-station and multi-stationsystems. Embodiments of the present disclosure provide for rotating thewafer without rotation of the pedestal, which advantageously filters outboth chamber and pedestal asymmetries.

Embodiments of the disclosure include an assembly for use in a processchamber for depositing a film on a wafer. The assembly includes apedestal having a pedestal top surface extending from a central axis ofthe pedestal to a pedestal diameter. The assembly includes an actuatorconfigured for controlling movement of the pedestal. The assemblyincludes a central shaft extending between the actuator and thepedestal, wherein the central shaft is configured to move the pedestalalong the central axis. The assembly includes a lift pad having a padtop surface extending from the central axis to a pad diameter and a padbottom surface configured to rest upon the pedestal top surface. The padtop surface is configured to support a wafer when placed thereon. Theassembly includes a pad shaft extending between the actuator and thelift pad, wherein the actuator is configured for controlling movement ofthe lift pad. The pad shaft is configured to separate the lift pad fromthe pedestal, and wherein the pad shaft is positioned within the centralshaft. The lift pad is configured to move up relative to the pedestaltop surface along the central axis when the pedestal is in an upwardsposition, such that the lift pad is separated from the pedestal topsurface by a process rotation displacement. The lift pad is configuredto rotate relative to the pedestal top surface when separated from thepedestal between at least a first angular orientation and a secondangular orientation.

Other embodiments of the disclosure include an assembly for use in aprocess chamber for depositing a film on a wafer. The assembly includesa pedestal having a pedestal top surface extending from a central axisof the pedestal to a pedestal diameter, wherein the pedestal top surfaceis configured to support a wafer when placed thereon. The assemblyincludes a recess centered in the pedestal top surface, wherein therecess extends from the central axis to a recess diameter, the recesshaving a recess height, and the recess having a recess bottom surface.The assembly includes an actuator configured for controlling movement ofthe pedestal. the assembly includes a central shaft extending betweenthe actuator and the pedestal, wherein the central shaft is configuredto move the pedestal along the central axis. The assembly includes alift pad having a pad top surface extending from the central axis to apad diameter, wherein the lift pad is configured rest upon the recessbottom surface when situated within the recess. The assembly includes apad shaft extending between the actuator and the lift pad, wherein theactuator is configured for controlling movement of the lift pad. The padshaft is configured to separate the lift pad from the pedestal, whereinthe pad shaft is positioned within the central shaft. The lift pad isconfigured to move up relative to the pedestal top surface along thecentral axis when the pedestal is in an upwards position, such that thelift pad is separated from the pedestal top surface by a processrotation displacement. The lift pad is configured to rotate relative tothe pedestal top surface when separated from the pedestal between atleast a first angular orientation and a second angular orientation.

In another embodiment, a method for operating a process chamber fordepositing a film on a wafer is disclosed. The method includes placingthe wafer on an assembly, the assembly including a pedestal and a liftpad. The pedestal includes a pedestal top surface extending from acentral axis to a pedestal diameter, wherein the lift pad is configuredto rest on the pedestal. The method includes controlling movement of thepedestal up and down along the central axis. The method includes movingthe pedestal to a process position. The method includes performing afirst number of processing cycles, wherein the lift pad is in a firstangular orientation relative to the pedestal top surface. The methodincludes moving the pedestal to an upwards position. The method includesraising the lift pad upwards relative to the pedestal top surface alongthe central axis when the pedestal is in the upwards position such thatthe lift pad is separated from the pedestal top surface by a processrotation displacement, and such that the wafer disposed upon the liftpad is separated from the pedestal. The method includes rotating thelift pad relative to the pedestal top surface when separated from thepedestal top surface to a second angular orientation relative to thepedestal top surface. The method includes lowering the lift pad to restupon the pedestal. The method includes moving the pedestal to theprocess position. The method includes performing a second number ofprocessing cycles, wherein the lift pad is in the second angularorientation.

These and other advantages will be appreciated by those skilled in theart upon reading the entire specification and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments may best be understood by reference to the followingdescription taken in conjunction with the accompanying drawings.

FIG. 1 illustrates a substrate processing system, which is used toprocess a wafer, e.g., to form films thereon.

FIG. 2 illustrates a top view of a multi-station processing tool,wherein four processing stations are provided, in accordance with oneembodiment.

FIG. 3 shows a schematic view of an embodiment of a multi-stationprocessing tool with an inbound load lock and an outbound load lock, inaccordance with one embodiment.

FIG. 4 illustrates a substrate processing system including a lift padand pedestal configuration, wherein the lift pad is approximately sizedto match a wafer, in accordance with one embodiment of the presentdisclosure.

FIG. 5A is a cross-sectional view of the substrate processing system ofFIG. 4, in accordance with one embodiment of the present disclosure.

FIG. 5B is a cross-sectional diagram of the substrate processing systemof FIG. 4 showing a lift pad and pedestal configuration, wherein thelift pad is approximately sized to match a wafer, and wherein thepedestal and lift pad are at a level allowing for lift pin extension forpurposes of wafer delivery, in accordance with one embodiment of thepresent disclosure.

FIG. 5C is a diagram of the interface between the lift pad and pedestalto include pad gap setting minimum contact areas (MCAs), in accordancewith one embodiment of the present disclosure.

FIG. 6 illustrates a substrate processing system including a lift padand pedestal configuration, wherein the lift pad is smaller than awafer, in accordance with one embodiment of the present disclosure.

FIG. 7A is a perspective view of the substrate processing system of FIG.6 including a lift pad and pedestal configuration, wherein the lift padis smaller than a wafer, in accordance with one embodiment of thepresent disclosure.

FIG. 7B is a cross-sectional diagram of the substrate processing systemof FIG. 6 including a lift pad and pedestal configuration, wherein thelift pad is smaller than a wafer, in accordance with one embodiment ofthe present disclosure.

FIG. 7C is a cross-sectional diagram of the substrate processing systemof FIG. 6 including a lift pad and pedestal configuration that includesa lift pin assembly, wherein the lift pad is smaller than a wafer, inaccordance with one embodiment of the present disclosure.

FIG. 7D is a cross-sectional diagram of the lift pad to pedestalinterface in the substrate processing system of FIG. 6 that includes alift pad and pedestal configuration, wherein the lift pad is smallerthan a wafer, in accordance with one embodiment of the presentdisclosure.

FIG. 7E is a perspective view of the top surface of the lift pad in thesubstrate processing system of FIG. 6 that includes a lift pad andpedestal configuration, in accordance with one embodiment of the presentdisclosure.

FIG. 7F is a perspective view of the bottom surface of the lift pad inthe substrate processing system of FIG. 6 that includes a lift pad andpedestal configuration, in accordance with one embodiment of the presentdisclosure.

FIG. 8 is a flow diagram illustrating a method for operating a processchamber configured for depositing a film on a wafer, wherein the methodprovides for rotating the wafer without rotation of the pedestal withinthe process chamber during processing, which advantageously filters outboth chamber and pedestal asymmetries, in accordance with one embodimentof the present disclosure.

FIGS. 9A and 9B are diagrams illustrating the motion sequence of a liftpad and pedestal configuration, wherein the lift pad is approximatelysized to match a wafer, and includes the rotation of the wafer withoutrotation of the pedestal within a process chamber during processing,which advantageously filters out both chamber and pedestal asymmetries,in accordance with one embodiment of the present disclosure.

FIG. 9C is a diagram illustrating the orientation of a lift pad withrespect to a pedestal in a lift pad and pedestal configuration, whereinthe lift pad is approximately sized to a wafer, during a first processsequence, a rotation sequence, and a second process sequence, inaccordance with one embodiment of the present disclosure.

FIGS. 10A and 10B are diagrams illustrating the motion sequence of alift pad and pedestal configuration, wherein the lift pad is smallerthan a wafer, wherein the lift pad is configured to allow for deliveryof the wafer (e.g., via an end-effector arm), and includes the rotationof the wafer without rotation of the pedestal within a process chamberduring processing, which advantageously filters out both chamber andpedestal asymmetries, in accordance with one embodiment of the presentdisclosure.

FIG. 10C is a diagram illustrating the motion sequence of a lift pad andpedestal configuration and including a lift pin assembly, wherein thelift pad is smaller than a wafer, and includes the rotation of the waferwithout rotation of the pedestal within a process chamber duringprocessing, which advantageously filters out both chamber and pedestalasymmetries, in accordance with one embodiment of the presentdisclosure.

FIG. 10D is a diagram illustrating the orientation of a lift pad withrespect to a pedestal in a lift pad and pedestal configuration, whereinthe lift pad is smaller than a wafer, during a first process sequence, arotation sequence, and a second process sequence, in accordance with oneembodiment of the present disclosure.

FIG. 11 shows a control module for controlling the systems describedabove.

DETAILED DESCRIPTION

Although the following detailed description contains many specificdetails for the purposes of illustration, anyone of ordinary skill inthe art will appreciate that many variations and alterations to thefollowing details are within the scope of the present disclosure.Accordingly, the aspects of the present disclosure described below areset forth without any loss of generality to, and without imposinglimitations upon, the claims that follow this description.

Generally speaking, the various embodiments of the present disclosuredescribe systems and methods that provide for improved film uniformityduring wafer processing (e.g., PECVD and ALD processes) insingle-station and multi-station systems. In particular, embodiments ofthe present disclosure provide for rotating the wafer without rotatingthe pedestal in order to filter out both chamber and pedestalasymmetries. In that manner, azimuthal nonuniformities due to chamberand pedestal asymmetries are minimized to achieve film uniformity acrossthe entire wafer during processing (e.g., PECVD, ALD, etc.).

With the above general understanding of the various embodiments, exampledetails of the embodiments will now be described with reference to thevarious drawings. Similarly numbered elements and/or components in oneor more figures are intended to generally have the same configurationand/or functionality. Further, figures may not be drawn to scale but areintended to illustrate and emphasize novel concepts. It will beapparent, that the present embodiments may be practiced without some orall of these specific details. In other instances, well-known processoperations have not been described in detail in order not tounnecessarily obscure the present embodiments.

FIG. 1 illustrates a reactor system 100, which may be used to depositfilms over substrates, such as those formed in atomic layer deposition(ALD) processes. These reactors may utilize two or more heaters, and thecommon terminal configurations may be used in this example reactor tocontrol the temperatures for uniformity or custom settings. Moreparticularly, FIG. 1 illustrates a substrate processing system 100,which is used to process a wafer 101. The system includes a chamber 102having a lower chamber portion 102 b and an upper chamber portion 102 a.A center column is configured to support a pedestal 140, which in oneembodiment is a powered electrode. The pedestal 140 is electricallycoupled to power supply 104 via a match network 106. The power supply iscontrolled by a control module 110, e.g., a controller. The controlmodule 110 is configured to operate the substrate processing system 100by executing process input and control 108. The process input andcontrol 108 may include process recipes, such as power levels, timingparameters, process gasses, mechanical movement of the wafer 101, etc.,such as to deposit or form films over the wafer 101.

The center column also includes lift pins (not shown), each of which isactuated by a corresponding lift pin actuation ring 120 as controlled bylift pin control 122. The lift pins are used to raise the wafer 101 fromthe pedestal 140 to allow an end-effector to pick the wafer and to lowerthe wafer 101 after being placed by the end-effector. The substrateprocessing system 100 further includes a gas supply manifold 112 that isconnected to process gases 114, e.g., gas chemistry supplies from afacility. Depending on the processing being performed, the controlmodule 110 controls the delivery of process gases 114 via the gas supplymanifold 112. The chosen gases are then flown into the shower head 150and distributed in a space volume defined between the showerhead 150face that faces that wafer 101 and the wafer 101 resting over thepedestal 140. In ALD processes, the gases can be reactants chosen forabsorption or reaction with absorbed reactants.

Further, the gases may be premixed or not. Appropriate valving and massflow control mechanisms may be employed to ensure that the correct gasesare delivered during the deposition and plasma treatment phases of theprocess. Process gases exit chamber via an outlet. A vacuum pump (e.g.,a one or two stage mechanical dry pump and/or a turbomolecular pump)draws process gases out and maintains a suitably low pressure within thereactor by a close loop controlled flow restriction device, such as athrottle valve or a pendulum valve.

Also shown is a carrier ring 200 that encircles an outer region of thepedestal 140. The carrier ring 200 is configured to sit over a carrierring support region that is a step down from a wafer support region inthe center of the pedestal 140. The carrier ring includes an outer edgeside of its disk structure, e.g., outer radius, and a wafer edge side ofits disk structure, e.g., inner radius, that is closest to where thewafer 101 sits. The wafer edge side of the carrier ring includes aplurality of contact support structures which are configured to lift thewafer 101 when the carrier ring 200 is lifted by spider forks 180. Thecarrier ring 200 is therefore lifted along with the wafer 101 and can berotated to another station, e.g., in a multi-station system. In otherembodiments, the chamber is a single station chamber.

FIG. 2 illustrates a top view of a multi-station processing tool,wherein four processing stations are provided. This top view is of thelower chamber portion 102 b (e.g., with the top chamber portion 102 aremoved for illustration), wherein four stations are accessed by spiderforks 226. Each spider fork, or fork includes a first and second arm,each of which is positioned around a portion of each side of thepedestal 140. In this view, the spider forks 226 are drawn indash-lines, to convey that they are below the carrier ring 200. Thespider forks 226, using an engagement and rotation mechanism 220 areconfigured to raise up and lift the carrier rings 200 (i.e., from alower surface of the carrier rings 200) from the stationssimultaneously, and then rotate at least one or more stations beforelowering the carrier rings 200 (where at least one of the carrier ringssupports a wafer 101) to a next location so that further plasmaprocessing, treatment and/or film deposition can take place onrespective wafers 101.

FIG. 3 shows a schematic view of an embodiment of a multi-stationprocessing tool 300 with an inbound load lock 302 and an outbound loadlock 304. A robot 306, at atmospheric pressure, is configured to movesubstrates from a cassette loaded through a pod 308 into inbound loadlock 302 via an atmospheric port 310. Inbound load lock 302 is coupledto a vacuum source (not shown) so that, when atmospheric port 310 isclosed, inbound load lock 302 may be pumped down. Inbound load lock 302also includes a chamber transport port 316 interfaced with processingchamber 102 b. Thus, when chamber transport 316 is opened, another robot(not shown) may move the substrate from inbound load lock 302 to apedestal 140 of a first process station for processing.

The depicted processing chamber 102 b comprises four process stations,numbered from 1 to 4 in the embodiment shown in FIG. 3. In someembodiments, processing chamber 102 b may be configured to maintain alow pressure environment so that substrates may be transferred using acarrier ring 200 among the process stations without experiencing avacuum break and/or air exposure. Each process station depicted in FIG.3 includes a process station substrate holder (shown at 318 for station1) and process gas delivery line inlets.

FIG. 3 also depicts spider forks 226 for transferring substrates withinprocessing chamber 102 b. The spider forks 226 rotate and enabletransfer of wafers from one station to another. The transfer occurs byenabling the spider forks 226 to lift carrier rings 200 from an outerundersurface, which lifts the wafer, and rotates the wafer and carriertogether to the next station. In one configuration, the spider forks 226are made from a ceramic material to withstand high levels of heat duringprocessing.

FIG. 4 illustrates a substrate processing system including a lift padand pedestal configuration 400, wherein the lift pad 430 isapproximately sized to match a wafer (not shown) disposed thereon, inaccordance with one embodiment of the present disclosure. In someembodiments, the lift pad 430 is approximately sized to allow forintegration with a carrier ring assembly. The lift pad and pedestalconfiguration 400 may be implemented within the systems of FIGS. 1-3,including multi-station and single-station processing tools.

The lift pad and pedestal configuration 400 includes a lift pad 430which is controlled by the lift pad control 455, and a pedestal 140′which is controlled by pedestal control 450. The central shaft 510′ iscoupled to the pedestal 140′, and the pad shaft 560 is coupled to thelift pad 430. The pedestal control 450 controls movement of the centralshaft 510′ in order to induce movement in the pedestal 140′. Forexample, the pedestal control 450 controls movement of the pedestal 140′(e.g., up and down along a central axis) during pre-processing,processing, and post-processing sequences. Lift pad control 455 controlsmovement of the lift pad shaft 560 in order to induce movement in thelift pad 430. For example, the lift pad control 455 controls movement ofthe lift pad 430 (e.g., up and down along the central axis 471, androtationally about the central axis 471) during pre-processing,processing, and post-processing sequences. In particular, the lift padand pedestal configuration 400 provides for rotation of the wafer with agreatly reduced hardware rotation signature compared to when rotatingthe whole pedestal 140′. That is, because the pedestal 140′ and/orchamber (not shown) remain fixed in relation to the lift pad 430 whilethe wafer is rotated, both pedestal and chamber based asymmetries arefiltered out, thereby significantly reducing hardware pedestal andchamber signatures exhibited on the wafer during processing. That is,the non-uniformities introduced by the pedestal signature can besymmetrically distributed throughout the wafer during wafer processingthrough wafer rotation using a lift pad, and without rotating thepedestal.

The lift pad and pedestal configuration 400 includes a plurality ofheating elements 470 that is used to directly heat the pedestal 140′(e.g., through conduction), and indirectly heat the lift pad 430 whendisposed on the pedestal 140′. In addition, the lift pad and pedestalconfiguration 400 optionally includes a plurality of cooling elements480 for cooling the pedestal 140′, in some process modules.

The lift pad and pedestal configuration 400 includes a center columnthat is shown to include a coaxial lift pin assembly 415 having aplurality of lift pins, controlled by the lift pin control 122, aspreviously described. For example, the lift pins are used to raise thewafer from the lift pad 430 and pedestal 140′ to allow an end-effectorto pick-up the wafer and to lower the wafer after being placed by theend-effector during wafer delivery sequences.

The lift pad and pedestal configuration 400 includes bellows 420. Thebellows 420 are individually coupled to the lift pin assembly 415,pedestal, or lift pad and are configured for movement of the lift pins,pedestal, or lift pad. In addition, the lift pad and pedestalconfiguration 400 includes a rotation motor 427 in a belt-pulleyarrangement. Further, the ferroseal 425 facilitates rotation of the liftpad 430 in a vacuum environment.

In one embodiment, the wafer sized lift pad 430 is electrostatic chuck(ESC) compatible. The ESC 570 is configured to include electrodes biasedto a high voltage in order to induce an electrostatic holding force tohold the wafer in position while the ESC 570 is active. Further, in oneembodiment, the lift pad and pedestal configuration 400 includes acompliant shaft section 435 that promotes a uniform gap between the liftpad 430 and the pedestal 140′, especially as the lift pad 430 is movedto rest on the pedestal 140′.

As shown in FIG. 4, in one embodiment, ball screw 437 (e.g., lefthanded) is configured to drive the lift pins counter to pedestal 140′during one sequence of processing. For example, ball screw 437 may beengaged during the wafer delivery sequence in order to extend the liftpins while the pedestal 140′ is moved near to or at a bottom-mostposition for wafer delivery. The ball screw 443 (e.g., right-handed) isused to move the pedestal along the central axis in Z. For example, theball screw 443 is configured to drive the pedestal 140′ in theZ-direction along the central axis using the Z-motor 445. In addition, ashort-stroke coupling mechanism 440 is shown.

FIG. 5A is a cross-sectional view of the substrate processing system ofFIG. 4, in accordance with one embodiment of the present disclosure. Inparticular, FIG. 5A illustrates the lift pad and pedestal configuration400, wherein the lift pad 430 is approximately sized to match a wafer(not shown).

For purposes of illustration only, the pedestal 140′ is formed in threesegments to accommodate during manufacturing the plurality of heatingelements 470 and the plurality of cooling elements 480. It isappreciated that the pedestal 140′ is considered to be one element, andmay be formed using any suitable manufacturing process.

As shown in FIG. 5A, the pedestal 140′ and lift pad 430 are at a levelallowing for extension of the lift pins 557 for purposes of waferdelivery. Each of the lift pins 557 is coupled to a corresponding liftpin support 555 to effect movement, wherein movement of the lift pinsupports 555 are controlled by lift pin control 122. In one embodiment,the pedestal 140′ is at a bottommost position along its Z travel alongthe central axis 471.

As previously described, the pedestal control 450 controls movement ofthe central shaft 510′. Because pedestal 140′ is coupled to the centralshaft 510′, movement in the central shaft 510′ is translated to thepedestal 140′. In addition, as previously described, the lift padcontrol 455 controls movement of the pad shaft 560. Because lift pad 430is coupled to the pad shaft 560, movement in the pad shaft 560 istranslated to the lift pad 430.

FIG. 5B is a cross-sectional diagram of the substrate processing systemof FIG. 4 showing an assembly 500B including the lift pad and pedestalconfiguration 400, previously introduced in FIGS. 4 and 5A, inaccordance with one embodiment of the present disclosure. The lift pad430 is approximately sized to match a wafer (not shown). In stillanother embodiment, the diameter of the lift pad 430 is sized toaccommodate a carrier ring (not shown). The lift pad and pedestalconfiguration 500B provides for improved film uniformity duringdeposition processes (e.g., PECVD, ALD, etc.) in single-station andmulti-station systems by rotating the wafer using a lift pad withoutrotating a pedestal in order to filter out azimuthal nonuniformities dueto chamber and pedestal asymmetries. In particular, the lift pad 430that rotates is much thinner than the whole pedestal 140′, and thus therotation signature of the lift pad 430 is much less than the rotationsignature (asymmetric hardware contributions to nonuniformities) of thepedestal 140′, which contains the heater elements 470 and coolingelements 480. That is, the non-uniformities introduced by the pedestalsignature can be symmetrically distributed throughout the wafer duringwafer processing through wafer rotation using a lift pad, and withoutrotating the pedestal.

In the assembly 500B, the pedestal 140′ includes a pedestal top surface533, which extends from a central axis 471 of the pedestal 140′. The topsurface 533 may include one or more recesses to provide an interfacebetween the pedestal 140′ and the lift pad 430, such as a recess in thecenter of the top surface 533 and centered about axis 471 that isconfigured to facilitate coupling between the pad shaft 560 and the liftpad 430, and a recess forming the outer rim 509. While the pedestal 140′may be described as generally having a circular shape when viewed fromabove and extending to a pedestal diameter, the footprint of thepedestal 140′ may vary from a true circle to accommodate for differentfeatures, such as a carrier ring support and end-effector access, etc.

As shown, pedestal 140′ is connected to the actuator 515, which isconfigured for controlling movement of the pedestal 140′. In particular,the pedestal control 450 is coupled to the actuator 515 in order tocontrol movement of the pedestal 140′. That is, a central shaft 510′ iscoupled to the actuator 515 and the pedestal 140′, such that the centralshaft 510′ extends between the actuator 515 and the pedestal 140′. Thecentral shaft 510′ is configured to move the pedestal 140′ along thecentral axis 471. As such, movement of the actuator 515 translates intomovement of the central shaft 510′, which in turn translates intomovement of the pedestal 140′.

In addition, the pedestal 140′ is shown having three segments 140 a′,140 b′, and 140 c′ for purposes of illustration only. For example,pedestal 140′ may be formed in three segments to accommodate forformation during manufacturing the plurality of heating elements 470and/or the plurality of cooling elements 480. As previously disclosed,it is appreciated that pedestal 140′ is considered to be one element,and may be formed using any suitable manufacturing processes.

In the assembly 500B, the lift pad 430 includes a pad top surface 575that extends from the central axis 471. In one embodiment, the pad topsurface 575 extends to the pad diameter 577. The lift pad 430 includes apad bottom surface 543 that is configured to rest upon the pedestal topsurface 533. In addition, the pad top surface 575 is configured tosupport a wafer when placed thereon.

In addition, the lift pad 430 is electrostatic chuck (ESC) compatible,as previously described. For example, an ESC assembly 570 is disposedbelow the pad top surface 575. The electrostatic chuck assembly 570prevents wafer movement due to chamber flow disturbances and maximizescontact of the wafer to the chuck (i.e., to the lift pad top surface575). A benefit to the lift pad 430 sized approximately to a wafercombined with a full-wafer ESC results in minimal wafer backsidedeposition. In addition, the full-wafer ESC does not require declampingin order to twist and/or rotate.

As shown, lift pad 430 is connected to the actuator 515, which isconfigured for controlling movement of the lift pad 430. The lift padcontrol 455 is coupled to the actuator 515 in order to control movementof the lift pad 430. That is, a pad shaft 560 is coupled to the actuator515 and the pedestal 140′, such that the pad shaft 560 extends betweenthe actuator 515 and the pedestal 140′. The pad shaft 560 is configuredwithin the central shaft 510′ that is connected to the pedestal 140′. Inparticular, the pad shaft 560 is configured to move the pedestal 140′along the central axis 471. As such, movement of the actuator 515translates into movement of the pad shaft 560, which in turn translatesinto movement of the lift pad 430. In one embodiment, the actuator 515controls movement of both the lift pad 430 and the pedestal 140′.

Specifically, the pad shaft 560 is configured to separate the lift pad430 from the pedestal 140′, as will be described more fully below inrelation to FIGS. 9A-9C. For example, the lift pad 430 is configured tomove up relative to the pedestal top surface 533 along the central axis471 when the pedestal 140′ is in an upwards position, such that the liftpad 430 is separated from the pedestal top surface 533 by a processrotation displacement for purposes of rotation of the lift pad 430. Inone embodiment, the lift pad 430 moves up relative to the pedestal topsurface 533 when the pedestal 140′ has reached a topmost upwardsposition. Further, when the lift pad 430 is separated from the pedestaltop surface 533, the lift pad 430 is configured to rotate relative tothe pedestal top surface 533 of the pedestal 140′ between at least afirst angular orientation and a second angular orientation (e.g.,between 0 degrees and 180 degrees). The pad shaft 560 is also configuredto lower the lift pad 430 to rest upon the pedestal 140′. In particular,a flexible coupler 435 (shown in FIG. 5C) is positioned within the padshaft 560, and is configured to position the lift pad 430 uniformlyabove the pedestal 140′.

To prepare for lift pad 430 rotation, the lift pad 430 moves upwards inrelation to the pedestal 140′, in one embodiment. That is, the lift pad430 is configured to move up relative to the pedestal top surface 533along the central axis 471 when the pedestal 140′ is in an upwardsposition (e.g., topmost upwards position) during wafer processing, suchthat the lift pad 430 is separated from the pedestal top surface 533 bya process rotation displacement 940 (see FIG. 9B), and such that thewafer disposed upon the lift pad 430 is also separated from the pedestal140′. In particular, when the lift pad 430 is separated from thepedestal 140′, the lift pad 430 is configured to rotate relative to thepedestal top surface 533 between at least a first angular orientationand a second angular orientation. This rotation reduces the effects ofthe hardware signature of the pedestal during processing, and alsoreduces the effects of the chamber hardware signature during processing.Additionally, the focus ring (not shown) does not rotate with the wafer,thereby reducing its hardware signature on the wafer during processing.

The assembly 500B includes a lift pin assembly that includes a pluralityof lift pins 557. For purposes of illustration, the pedestal 140′ andlift pad 430 are at a level allowing for lift pin 557 extension forpurposes of wafer delivery, in accordance with one embodiment of thepresent disclosure. In particular, the lift pins 557 extend from thelift pad 430 through a plurality of pedestal shafts 518 disposed in thepedestal 140′ and through a plurality of lift pad shafts 519 in the liftpad 430 in such a manner such that an end-effector arm (not shown)carrying a wafer (with or without a carrier ring) is able to maneuverinto a position for delivering the wafer to the lift pins 557 or forreceiving the wafer from the lift pins 557. Corresponding pedestalshafts 518 and pad shafts 519 are aligned and configured to receive acorresponding lift pin 557. As shown, one or more lift pin shafts andcorresponding lift pins may be configured within the lift pin assemblyto lift up and place or remove the wafer during wafer delivery. Asshown, each of the lift pins 557 is coupled to a corresponding lift pinsupport 555 to effect movement. The lift pin supports 555 are coupled toa lift pin actuator 550. In addition, the lift pin control 122 controlsmovement of the lift pin actuator 550 to effect movement in the liftpins 557.

The lift pin support 555 may be of any shape (e.g., annular ring washer,arm extending from an annular base, etc.). In particular, duringoperation of the lift pin assembly, the lift pin 557 is attached to thelift pin support 555, and positioned to move within the lift pin shaftto raise the wafer above the lift pad top surface 575 and/or to lowerthe wafer to rest upon the pad top surface 575 during wafer delivery andprocessing.

FIG. 5C is a diagram of the interface between the lift pad 430 andpedestal 140′ that includes pad gap setting minimum contact areas (MCAs)to control and/or mechanically set the gap, especially during processsequences, in accordance with one embodiment of the present disclosure.This results in a uniform temperature and impedance control of the pad.The interface shown in FIG. 5C is exemplary of the interfaces betweenthe lift pads and pedestals shown in FIGS. 5A and 5B.

It is advantageous for the gap between the lift pad 430 and the pedestal140′ to be uniform and small for deposition processes. For example,PECVD and ALD processing can exhibit non-uniformity signatures duetemperature and plasma impedance for instance. Both factors aresensitive to the gap between the wafer and the pedestal. Minimizing thesize of the gap, and controlling the uniformity of the gap across thelift pad and pedestal configuration reduces the signatures caused bytemperature and plasma impedance.

In particular, a small gap allows low impedance coupling of radiofrequency (RF) energy between the lift pad 430 and the pedestal 140′. Inaddition, a small gap provides for lower thermal resistance, therebyallowing heating and/or cooling to easily conduct from the pedestal 140′to the lift pad 430. Further, a uniform gap between the lift pad 430 andthe pedestal 140′ ensures uniform heat transfer and uniform RF coupling.

As shown, the pedestal top surface 533 includes a plurality of padsupports 595 (e.g., pad gap setting MCAs) defined thereon, wherein thepad supports are configured to support the lift pad 430 at a pad supportlevel above the pedestal top surface 533. Segments 140 a′ and 140 b′ ofthe pedestal 140′ are shown in FIG. 5C. As previously described, the padsupports 595 provide for a uniform and small gap between the lift pad430 and the pedestal 140′, thereby ensuring uniform heat transfer anduniform RF coupling between the lift pad 430 and the pedestal 140′. Moreparticularly, the bottom surface 543 of the lift pad 430 is configuredto rest upon the plurality of pad supports 595 of the pedestal 140′. Forexample, the pedestal 140′ and lift pad 430 can be configured in aprocess position (e.g., when performing plasma processing, treatmentand/or film deposition), or in a pre-coat position, such that the liftpad 430 is resting upon the plurality of pad supports 595. In addition,the lift pad 430 is configured to move with the pedestal 140′ whenresting upon the pad supports 595. Pad supports may be electricallyconductive for DC, low frequency, and radio frequency transmission.

FIG. 6 illustrates a substrate processing system including a lift padand pedestal configuration 600, wherein the lift pad 630 is smaller thana wafer (not shown), in accordance with one embodiment of the presentdisclosure. The lift pad and pedestal configuration 600 may beimplemented within the systems of FIGS. 1-3, including multi-station andsingle-station processing tools

The lift pad and pedestal configuration 600 includes a lift pad 630which is controlled by the lift pad control 455, and a pedestal 140″which is controlled by pedestal control 450. As previously described,pedestal control 450 controls movement of pedestal 140″ along a centralaxis 471′, and lift pad control 455 controls movement of the lift pad630 about the central axis 471′ (e.g., up, down, and rotationally). Thelift pad and pedestal configuration 600 provides for rotation of thewafer (not shown) via the lift pad 630 with a greatly reduced hardwarerotation signature when compared to a processing tool having pedestalrotation or no pedestal rotation.

The lift pad and pedestal configuration 600 includes a small lift pad630 that is smaller than a wafer footprint. The lift pad and pedestalconfiguration 600 may be suitable for some deposition processes when anESC is not selected. In that case, the small lift pad 630 is preferable,since it allows pedestal minimum contact areas (MCAs) that support thewafer during the process to not rotate with the wafer. In that case, thegapping of the wafer nominally does not rotate with the wafer, whichreduces exposure to hardware asymmetry. In addition, the smaller liftpad 630 also offers further benefits in that a reduced mass needs to berotated, which provides less mechanical stresses on the system.

The lift pad and pedestal configuration 600 includes a plurality ofheating elements 470′ and thermocouple 607, which is included in the padshaft 560′ of the lift pad 630 in order to match the temperature at thesurface of the lift pad 630 to the surface of the pedestal 140″. Coolingelements in the pedestal 140″ may be included in some process modules.

In one embodiment, though not shown, the lift pad and pedestalconfiguration 600 optionally includes a lift pin assembly having aplurality of lift pins that is controlled by lift pin control 122 toprovide for wafer delivery, as previously described. Flange 605 isincluded in the co-axial lift pin assembly (not shown). In anotherembodiment, the small lift pad 630 may be used to provide lift pinfunctionality, eliminating the need for the lift pin assembly, andtherefore providing cost and packaging advantages.

The lift pad and pedestal configuration 600 includes bellows 420′ eachof which is individually coupled to the optional lift pin assembly,pedestal 140″, or lift pad 630 and are configured for movement thereof.In addition, lift pad and pedestal configuration 600 also includes arotation motor in a belt-pulley arrangement (not shown) that is similarto the one shown in FIG. 4. The ferroseal 425′ facilitates rotation ofthe lift pad 630 in a vacuum environment.

In addition, Z-motor 445′ is configured to drive the pedestal 140″ inthe Z-direction along a central axis 471′. In addition, a coupledmechanism driven slide 603 is attached to the pedestal and central shaft510″, and is attached to the ball screw attached to the Z-motor 445′,all of which are used to facilitate movement of the pedestal 140″ alongthe central axis 471′.

FIG. 7A is a perspective view of the substrate processing system of FIG.6, in accordance with one embodiment of the present disclosure. Inparticular, FIG. 7A includes the lift pad and pedestal configuration600, wherein the lift pad 630 is smaller than a wafer (not shown). Asshown in FIG. 7A, the pedestal 140″ and the lift pad 630 are shown atpositions and/or levels allowing for wafer processing.

As previously described, pedestal control 450 controls movement of thecentral shaft 510″. Because pedestal 140″ is coupled to the centralshaft 510″, movement in the central shaft 510″ is translated to thepedestal 140″. In addition, as previously described, the lift padcontrol 455 controls movement of the pad shaft 560′. Because the liftpad 630 is coupled to the pad shaft 560′, movement in the pad shaft 560′is translated to the lift pad 630.

The pedestal 140″ of the lift pad and pedestal configuration 600includes a pedestal top surface 720 extending from the central axis 471′of the pedestal 140″. A plurality of wafer supports 760 is disposed onthe top surface 720. In addition, a raised rim 710 is disposed on theouter edge of the pedestal top surface 720, wherein the raised rim 710is configured for blocking lateral movement of a wafer that is placed onthe pedestal 140″.

FIG. 7B is a cross-sectional diagram of the substrate processing systemof FIG. 6 showing an assembly 700B including a lift pad and pedestalconfiguration 600, previously introduced in FIGS. 6 and 7A, inaccordance with one embodiment of the present disclosure. The lift pad630 is sized smaller than a wafer, in accordance with one embodiment ofthe present disclosure. For purposes of illustration only, the pedestal140″ and the lift pad 630 are shown at positions and/or levels allowingfor wafer processing. The lift pad and pedestal configuration assembly700B provides for improved film uniformity during deposition processes(e.g., PECVD, ALD, etc.) in single-station and multi-station systems byrotating the wafer using a lift pad without rotating a pedestal in orderto filter out azimuthal nonuniformities due to chamber and pedestalasymmetries. In particular, the lift pad 630 that rotates is muchsmaller and thinner than the whole pedestal 140″, and thus the rotationsignature of the lift pad 630 is much less than the rotation signature(asymmetric hardware contributions to nonuniformities) of the pedestal140″, which contains the heating elements 470′. That is, thenon-uniformities introduced by the pedestal signature can besymmetrically distributed throughout the wafer during wafer processingthrough wafer rotation using a lift pad, and without rotating thepedestal.

In the assembly 700B, the pedestal 140″ includes a pedestal top surface720 extending from the central axis 471′ of the pedestal 140″. Thepedestal top surface 720 is configured to support a wafer when placedthereon. The top surface 720 may include one or more recesses to providean interface between the pedestal 140″ and the lift pad 630, such as arecess 705 configured to facilitate coupling between the pad shaft 560′and the lift pad 630, and a recess forming the outer rim 710. While thepedestal 140″ may be described as generally having a circular shape whenviewed from above and extending to a pedestal diameter, the footprint ofthe pedestal 140″ may vary from a circle to accommodate for differentfeatures, such as a carrier ring support, and end-effector access, etc.

As shown, pedestal 140″ is connected to the actuator 515′, which isconfigured for controlling movement of the pedestal 140″. In particular,the pedestal control 450 is coupled to actuator 515′ to control movementof the pedestal 140″. In particular, a central shaft 510″ is coupled tothe actuator 515′ and the pedestal 140″, such that the central shaft510″ extends between the actuator 515′ and the pedestal 140″. Thecentral shaft 510″ is configured to move the pedestal 140″ along thecentral axis 471′. As such, movement of the actuator 515′ translatesinto movement of the central shaft 510″, which in turn translates intomovement of the pedestal 140″.

In one embodiment, the pedestal top surface 720 includes a plurality ofwafer supports (not shown) defined thereon, wherein the wafer supportsare configured to support a wafer 590 at a wafer support level above thepedestal top surface 720. The wafer supports provide for a uniform andsmall gap between the pedestal 140″ and any wafer 590 disposed thereon.

The pedestal 140″ includes a recess 705 centered in the pedestal topsurface 720 and extending from the central axis 471′, the recess 705having a recess height, and wherein the recess 705 having a recessbottom surface 706. That is, recess 705 sits over a center portion ofthe pedestal top surface 720. In one embodiment, the recess bottomsurface 706 includes a plurality of pad supports defined thereon,wherein the pad supports (e.g., MCAs) are configured to support the liftpad 630 at a pad support level above the recess bottom surface 706. Inanother embodiment, MCAs are disposed on the bottom surface of the liftpad 630, as is further described in relation to FIG. 7F.

In addition, the pedestal 140″ is shown having two segments 140 a″ and140 b″, for purposes of illustration only. For example, pedestal 140″may be formed in two segments to accommodate for formation duringmanufacturing the plurality of heating elements 470′ and/or a pluralityof cooling elements (not shown). As previously disclosed, it isappreciated that pedestal 140″ is considered to be one element, and maybe formed using any suitable manufacturing processes

In the assembly 700B, the lift pad 630 includes a lift pad top surface775 that extends from the central axis 471′ to the pad diameter 777. Thelift pad 630 is configured rest upon the recess bottom surface 706 whensituated within the recess 705, wherein the recess 705 is configured toreceive the lift pad 630. In particular, the lift pad top surface 775 isbelow the wafer 590 when the wafer 590 sits on the wafer supports of thepedestal 140″, such as in a process position (e.g., when performingplasma processing, treatment and/or film deposition). That is, the liftpad top surface 775 sits under the wafer support level when the padbottom surface 632 of the lift pad 630 rests upon the plurality of padsupports (e.g., MCAs 745). Further, the lift pad 630 is configured tomove with the pedestal 140″ when resting upon the pad supports.

As shown, the lift pad 630 is connected to the actuator 515′, which isconfigured for controlling movement of the lift pad 630. For example,the lift pad control 455 is coupled to actuator 515′ in order to controlmovement of the lift pad 630. In particular, a pad shaft 560′ is coupledto the actuator 515′ and the pedestal 140″, such that the pad shaft 560′extends between the actuator 515′ and the pedestal 140″. The pad shaft560′ is configured within the central shaft 510″ that is connected tothe pedestal 140″. In particular, the pad shaft 560′ is configured tomove the lift pad 630 along the central axis 471′. As such, movement ofthe actuator 515′ translates into movement of the pad shaft 560′, whichin turn translates into movement of the lift pad 630. In one embodiment,the actuator 515′ controls movement of both the lift pad 630 and thepedestal 140″.

Specifically, the pad shaft 560′ is configured to separate the lift pad630 from the pedestal 140″ for lift pad rotation, as will be describedmore fully below in relation to FIGS. 10A-10D. For example, the lift pad630 is configured to move up relative to the pedestal top surface 720along the central axis 471′ when the pedestal 140″ is in an upwardsposition, such that the lift pad 630 is separated from the pedestal topsurface 720 by a process rotation displacement for purposes of rotatingthe lift pad 630. The pad shaft 560′ is also configured to lower thelift pad 630 to rest upon the pedestal 140″. In one embodiment, toprepare for lift pad rotation, the lift pad 630 moves upwards inrelation to the pedestal 140″. That is, the lift pad 630 is configuredto move up relative to the pedestal top surface 720 along the centralaxis 471′ when the pedestal 140″ is in the upwards position, such thatthe lift pad 630 is separated from the pedestal top surface 720 by aprocess rotation displacement 1040 (see FIGS. 10B and 10C), and suchthat the wafer disposed upon the lift pad 630 is separated from thepedestal 140″. In one embodiment, the pedestal 140″ is in the topmostupward position during lift pad 630 rotation. In particular, when thelift pad 630 is separated from the pedestal 140″, the lift pad 630 isconfigured to rotate relative to the pedestal top surface 720 between atleast a first angular orientation and a second angular orientation(e.g., between 0 degrees and 180 degrees). This rotation reduces theeffects of the hardware signature of the pedestal during processing, andalso reduces the effects of the chamber hardware signature duringprocessing.

In other embodiments, the lift pad 630 provides for lift pinfunctionality to raise and lower the wafer during wafer delivery andprocessing. Specifically, the lift pad 630 is configured to move uprelative to the central pedestal top surface 720 when the pedestal is ina bottommost downwards position, such that the lift pad 630 is separatedfrom the central pedestal top surface 720 by a displacement large enoughfor entry of an end-effector arm.

As shown in FIG. 7B, the pedestal 140″ of the lift pad and pedestalconfiguration 600 includes a raised rim 710 disposed on the outer edgeof the pedestal top surface 720, wherein the raised rim 710 isconfigured for blocking lateral movement of a wafer that is placed onthe pedestal 140″. That is, the rim 710 is a step above the pedestal topsurface 720 at a height sufficient to block movement of the wafer. Forexample, the raised rim 710 forms a groove blocking lateral movement ofthe wafer when the wafer rests on the pedestal top surface 720.

FIG. 7C is a cross-sectional diagram of the substrate processing systemof FIG. 6 showing an assembly 700C including a lift pad and pedestalconfiguration 600′, based on the configurations previously introduced inFIGS. 6, 7A and 7B, wherein the lift pad 630 is smaller than a wafer, inaccordance with one embodiment of the present disclosure. The lift padand pedestal configuration 600′ includes a pedestal 140′″ and lift pad630. More specifically, the lift pad and pedestal configuration 600′ ofFIG. 7C is similar to the lift pad and pedestal configuration 600 ofFIG. 7B, and provides the same benefits and advantages (e.g., improvedfill uniformity during deposition processes), previously described inrelation to FIG. 7B. That is, the non-uniformities introduced by thepedestal signature can be symmetrically distributed throughout the waferduring wafer processing through wafer rotation using a lift pad, andwithout rotating the pedestal. However, the lift pad and pedestalconfiguration 600′ also includes the lift pin assembly that isconfigured for delivery of a corresponding wafer (e.g., wafer 590).

The lift pin assembly of the assembly 700C includes a plurality of liftpins 557′. For purposes of illustration, the pedestal 140′″ and lift pad630 are at a level allowing for lift pin 557′ extension for purposes ofwafer delivery, in accordance with one embodiment of the presentdisclosure. In particular, the lift pins 557′ extend from a plurality ofpedestal shafts 518′ displaced from the central axis 471′ and disposedin the pedestal 140′″ in such a manner such that an end-effector arm(not shown) carrying a wafer (with or without a carrier ring) is able tomaneuver into a position for delivering the wafer to the lift pins 557′or for receiving the wafer from the lift pins 557′. Correspondingpedestal shafts 518′ are configured to receive a corresponding lift pin557′. As shown, one or more pedestal shafts 518′ and corresponding liftpins 557′ may be configured within the lift pin assembly to lift up andplace or remove the wafer during wafer delivery. As shown, each of thelift pins 557′ is coupled to a corresponding lift pin support 555′ andpositioned to move within the pedestal shaft 518′ to raise the waferabove the pedestal top surface 720 and/or to lower the wafer to thepedestal top surface 720 during wafer delivery and processing. The liftpin support 555′ is configured to move relative to the pedestal topsurface 720 in parallel to the central axis 471′. Further, the lift pinsupports 555′ are coupled to a lift pin actuator 550′. In addition, thelift pin control 122, previously introduced, controls movement of thelift pin actuator 550′ to effect movement in the lift pins 557′. Thelift pin support 555′ may be of any shape (e.g., annular ring washer,arm extending from an annular base, etc.).

FIG. 7D is a cross-sectional diagram of the lift pad to pedestalinterface in the substrate processing system of FIG. 6 that includes alift pad and pedestal configuration 600 or 600′ of FIGS. 7A-7C, whereinthe lift pad is smaller than a wafer, in accordance with one embodimentof the present disclosure.

High temperature bearing 755 is positioned within the pad shaft 560′ andis configured to position the lift pad 630 uniformly within the recess705 of pedestal 140″ or 140′″. To handle high temperatures, the wearsurfaces preferably made of a hard, chemically compatible material, suchas sapphire. The bearing centering is insensitive to relative thermalexpansion of the bearing components, the shaft, and pedestal materials.In one embodiment, the conical clamping surface of the sapphire bearingrings may be spring loaded using an assembly of load distributingwashers, spring washers, and retaining rings of material suitable forhigh temperature and corrosive operation. The bearing is clamped withmin energy at its centered position and remains centered with changes intemperature. A sapphire contact ring prevents indentation of the softerpedestal material.

In particular, the interface between lift pad 630 and the pedestal140″/140′″ is shown, and includes pad gap setting MCAs to control and/ormechanically set the gap, especially during process sequences. Forexample, FIG. 7D shows sapphire balls 740 and 745 (e.g., MCAs) swagedinto the lift pad 630. In particular, the balls 740 and 745 protrudeslightly above the corresponding surface on the order operating systemseveral millimeters at process temperature. The sapphire balls act tocontact the pedestal 140″/140′″ in a minimum contact area to minimizethermal conduction through the contact with a poor thermally conductingmaterial. Further, a sapphire contact ring prevents indenting of thesofter pedestal material.

For example, FIG. 7E is a perspective view of the top surface 631 of thelift pad 630 shown in FIG. 7D that includes MCAs 740, in accordance withone embodiment of the present disclosure. In one embodiment, the waferreferencing MCAs 740 are positioned at 0.002″ above the top surface 631,such that the pad top surface 631 is under the wafer support level whenthe lift pad 630 rests upon the recess bottom surface 706. The waferreferencing MCAs 740 do not contact the wafer 590 when the lift pad 630is resting on the pedestal 140″/140′″ because separate pedestal wafersupports (e.g., MCAs) located on the top surface 720 of the pedestal arehigher by approximately 0.002″ or more, in one embodiment. The wafersupports disposed on the pedestal top surface 720 of the pedestal140″/140′″ are configured to support the wafer 590 when placed thereonat a wafer support level above the top surface 720.

Also, FIG. 7F is a perspective view of the bottom surface 632 of thelift pad 630 shown in FIG. 7D that includes MCAs 745, in accordance withone embodiment of the present disclosure. In one embodiment, the waferreferencing MCAs 745 are 0.004″ above the bottom surface 632. Thisensures uniform, repeatable gapping between the lift pad 630 andpedestal 140″/140′″ to provide uniform, repeatable thermal resistance tothe pedestal 140″/140′″. In one embodiment, the MCAs 745 work inconjunction with a plurality of pad supports (not shown) disposed on therecess bottom surface 706, which are configured to support the lift pad630 at a pad support level above the recess bottom surface 706.

FIG. 8 is a flow diagram 800 illustrating a method for operating aprocess chamber configured for depositing a film on a wafer, wherein themethod provides for rotating the wafer without rotation of the pedestalwithin the process chamber during processing, which advantageouslyfilters out both chamber and pedestal asymmetries, in accordance withone embodiment of the present disclosure. Flow diagram 800 isimplemented within the systems and lift pad and pedestal configurationsof FIGS. 1-7, in embodiments of the present disclosure. The operationsin flow diagram 800 are applicable to the wafer-sized lift pad andpedestal configuration, as shown in FIGS. 4 and 5A5C in embodiments, andto a lift pad and pedestal configuration that includes a lift pad thatis sized to be smaller than a wafer, such as that shown in FIGS. 6, and7A-7F, in other embodiments.

At operation 805, the method includes moving the lift pad and pedestalconfiguration to a bottomwards position to receive a wafer. In oneembodiment, the pedestal is in its bottommost downwards position. In alift pad and pedestal configuration that includes a lift pin assembly,the lift pins may be extended for wafer delivery. In a lift pad andpedestal configuration that does not include a lift pin assembly, thelift pad (e.g., smaller than a wafer) may be separated from the pedestaltop surface by a displacement large enough for entry of an end-effectorarm for purposes of wafer delivery. At operation 810, a wafer is placedonto an assembly including the lift pad and pedestal configuration,wherein the lift pad is configured to rest upon the pedestal. Forexample, this may involve placing the wafer onto the extended lift pins,or placing the wafer on an extended lift pad. Lift pins or the lift padare lowered such that the wafer rests on the wafer supports of thepedestal top surface, lift pad top surface, or ESC chuck surface.

Pedestal movement is controlled, such that that the pedestal is moved upand down along the central axis of the pedestal. In one embodiment, acoupled mechanism translates movement of the pedestal to the lift pad inthe lift pad and pedestal configuration. For example, after the wafer isdelivered the lift pad and pedestal configuration is moved to a processposition at operation 820. In the process position, the lift pad restsupon the pedestal, as previously described. Further, the lift pad is ina first orientation in relation to the pedestal and/or the chamber. Thefirst orientation may be arbitrary. For example, both the lift pad andthe pedestal may be positioned at a 0 degree angular orientation withinthe chamber.

At operation 825, the method includes processing the wafer for a firstnumber of processing cycles at the first orientation. For example, thedeposition of one or more films may implement an atomic layer deposition(ALD) process, which is also known as atomic layer chemical vapordeposition (ALCVD). ALD produces very thin films that are highlyconformal, smooth, and possess excellent physical properties. ALD usesvolatile gases, solids, or vapors that are sequentially introduced (orpulsed) over a heated substrate. In one ALD cycle, four operations areperformed and can be defined as an A-P-B-P sequence. In step A, a firstprecursor is introduced as a gas, which is absorbed (or adsorbed) intothe substrate. In step P right after step A, the reactor chamber iscleared of the gaseous precursor. In step B, a second precursor isintroduced as a gas, which reacts with the absorbed precursor to form amonolayer of the desired material. In step P right after step B, thereactor chamber is again cleared of the gaseous second precursor. Byregulating this A-P-B-P sequence, the films produced by ALD aredeposited a monolayer at a time by repeatedly switching the sequentialflow of two or more reactive gases over the substrate. In that manner,the thickness of the film may be regulated depending on the number ofcycles performed of the A-P-B-P sequence. The first number of cycles maybe defined as value X. To illustrate the present embodiments thatdisclose a lift pad and pedestal configuration capable of rotating thewafer without rotation of the pedestal within the process chamber duringprocessing, which advantageously filters out both chamber and pedestalasymmetries, X number of cycles may be 50 cycles.

At operation 830, the method includes raising the pedestal to an upwardsposition. In one embodiment, the pedestal is raised to its topmostupwards position. By moving the pedestal to the upwards position, thelift pad is also raised upwards relative to the pedestal (e.g., topsurface of pedestal), such that the wafer disposed on the lift pad isseparated from the pedestal. In one embodiment, a coupled mechanismraises the lift pad when the pedestal nears the top of its travel. Thatis, the surface contact of the lift pad to pedestal is broken, whichallows the lift pad to rotate freely. In particular, the lift pad isseparated from the pedestal by a process rotation displacement (e.g., onthe order of 1 mm). In this manner, a wafer supported by or disposed onthe lift pad is also separated from the pedestal.

At operation 840, the method includes rotating the lift pad relative tothe pedestal (e.g., top surface of pedestal), when the lift pad isseparated from the pedestal. In particular, the lift pad is rotated fromthe first orientation to a second orientation relative to the pedestal.For example, the second orientation may be 180 degrees from the firstorientation (e.g., first orientation at 0 degrees).

At operation 845, the method includes lowering the lift pad to rest uponthe pedestal. Also, at operation 850, the method includes moving thepedestal, and correspondingly the lift pad, back to the processposition. In one embodiment, the operations performed at 845 and 850occur simultaneously through the action of the coupled mechanism, suchthat by lowering the pedestal back to the process position, the lift padis also lowered until the lift pad rests upon the pedestal.

At operation 855, the method includes processing the wafer for a secondnumber of processing cycles (e.g., each cycle includes an A-P-B-Psequence), wherein the lift pad is in the second orientation relative tothe pedestal. The second number of cycles may be defined as value Y. Toillustrate the present embodiments that disclose a lift pad and pedestalconfiguration capable of rotating the wafer without rotation of thepedestal within the process chamber during processing, whichadvantageously filters out both chamber and pedestal asymmetries, Ynumber of cycles may be 50 cycles.

In that manner, the thickness of the film may be regulated depending onthe total number of cycles (e.g., X+Y) performed of the A-P-B-Psequence. Because the wafer is also rotated with respect to the pedestalfor the second number of cycles, both chamber and pedestal asymmetriesare filtered out, which provides for improved film uniformity duringwafer processing.

In the example provided above, the first number of cycles is X, and thesecond number of cycles is Y, wherein both X and Y include 50 cycles fora total number of 100 cycles performing the A-P-B-P sequence. That is,the first number of processing cycles (X) may be one-half the totalnumber of cycles performed at a first orientation, and the second numberof processing cycles (Y) may also be one-half the total number of cyclesperformed at the second orientation. As such, 50 cycles are performed atthe first angular orientation (e.g., 0 degrees), and another 50 cyclesare performed at the second angular orientation (e.g., 180 degrees).

While embodiments of the present disclosure are described with referenceto a first and second orientation, other embodiments are well suited toperforming wafer processing using one or more orientations (e.g., 1, 2,3, etc.). The orientations may be separated by equal angles in oneembodiment, or may be separated by unequal angles in another embodiment.Further, at each orientation, one or more cycles of wafer processing(e.g., ALD, PECVD, etc.) are performed. The number of cycles performedat each orientation may be distributed equally in one embodiment, or maybe distributed unequally in another embodiment. That is, otherembodiments are well suited to two or more sets of cycles at two or morerelative angular orientations (e.g., between the lift pad and pedestal),wherein each set may include equal numbers of processing cycles (e.g.,each cycle includes an A-P-B-P sequence), or different numbers ofprocessing cycles.

At operation 860, the method includes moving the lift pad and pedestalconfiguration to a bottomwards position for wafer removal from theassembly including the lift pad and pedestal configuration. In oneembodiment, the pedestal is in its bottommost downwards position. Aspreviously described, in a lift pad and pedestal configuration thatincludes a lift pin assembly, the lift pins may be extended for waferdelivery. In a lift pad and pedestal configuration that does not includea lift pin assembly, the lift pad (e.g., smaller than a wafer) may beseparated from the pedestal top surface by a displacement large enoughfor entry of an end-effector arm for purposes of wafer delivery. Assuch, the wafer may be removed from the extended lift pins, or extendedlift pad, using the end-effector arm.

FIGS. 9A and 9B are diagrams illustrating the motion sequence of a liftpad and pedestal configuration, wherein the lift pad is approximatelysized to match a wafer, and includes the rotation of the wafer withoutrotation of the pedestal within a process chamber during processing,which advantageously filters out both chamber and pedestal asymmetries,in accordance with one embodiment of the present disclosure.

In particular, FIG. 9A shows the wafer sized lift pad and pedestalconfiguration 400, first introduced in FIGS. 4 and 5A-5B. The lift padand pedestal configuration 400 includes a pedestal 140′, lift pad 430,and a lift pin assembly including lift pins 557. In the deliveryposition, the lift pad and pedestal configuration 400 is configured suchthat the pedestal 140′ is at a bottomwards position with the lift padresting on the pedestal. As shown in the dotted circle labeled “A,” thelift pins 557 are extended from the top surface of the lift pad 430 forpurposes of wafer delivery. FIG. 9A also shows the lift pad and pedestalconfiguration 400 in the pre-coat position, wherein pre-coat andundercoat layers of the film are deposited in the process chamber beforewafers are processed. As shown in the dotted circle labeled “B,” thelift pad 430 rests upon the pedestal 140′. In addition, the lift pins557 are positioned such that the tops of the lift pins 557 just fill theholes corresponding to pad shafts in the lift pad 430, which is anappropriate position during chamber pre-coat, when pre-coat depositionoccurs, and no wafer is on the lift pad and pedestal configuration 400.FIG. 9A also shows the lift pad and pedestal configuration 400 in theprocess position, wherein one or more films may be deposited (e.g.,PECVD and ALD processes) during wafer processing in single-station andmulti-station systems. For example, wafer processing may implement anatomic layer deposition (ALD) process, which is also known as atomiclayer chemical vapor deposition (ALCVD). ALD produces very thin filmsthat are highly conformal, smooth, and possess excellent physicalproperties. As previously introduced, four operations are performed inone ALD cycle (e.g., the A-P-B-P sequence). As shown in the dottedcircle labeled “C,” the lift pad 430 rests upon the pedestal 140′, andthe lift pins 557 have retreated to a position within the body of thepedestal 140′. FIG. 9A also shows the lift pad and pedestalconfiguration 400 in the rotation position, wherein the pedestal is atan upwards position (e.g., topmost upwards position). As shown in thedotted circle labeled “D,” the lift pad 430 is separated from thepedestal 140′ by a process rotation displacement, such that the lift padmay be rotated to a second angular orientation in relation to thepedestal 140′.

FIG. 9B provides more details to FIG. 9A, and illustrate the motionsequence of the lift pad and pedestal configuration 400, firstintroduced in FIGS. 4 and 5A-5B, wherein the lift pad is approximatelysized to match a wafer, and includes the rotation of the wafer withoutrotation of the pedestal within a process chamber during processing,which advantageously filters out both chamber and pedestal asymmetries,in accordance with one embodiment of the present disclosure.

In the delivery position, the lift pad and pedestal configuration 400 isconfigured such that the pedestal 140′ is at a bottomwards position withthe lift pad 430 resting on the pedestal 140′. In particular, the liftpad and pedestal configuration 400 is at a delivery position ready toreceive and/or remove a wafer, such that the bottom of pedestal 140′ isat a level within the corresponding chamber indicated by line 901. Inparticular, in one embodiment the pedestal 140′ is at its bottommostlevel, and is lower than the pre-coat position wherein the bottom ofpedestal 140′ is at a level indicated by line 902, as well as the levelindicated by line 903 associated with a process position, and the levelindicated by line 904 associated with a rotation position. As shown, thelift pad 430 rests upon pedestal 140′, as previously described. Inaddition, the lift pins 557 extend beyond the top surface of the liftpad 430, in a position to receive a wafer that is delivered by an arm ofan end-effector, for example.

FIG. 9B shows the lift pad and pedestal configuration 400 at a pre-coatlevel, wherein the bottom of the pedestal 140′ is at a level within acorresponding chamber indicated by line 902. It is important to notethat the pre-coat position may be defined at any position within thechamber, and is not limited to the level indicated by line 902. Forexample, the pre-coat position may be same as the process position,wherein the lift pad and pedestal configuration is positioned for waferprocessing (e.g., ALD, PECVD, etc.) As shown, the lift pad 430 restsupon the pedestal 140′, as previously described. In addition, the liftpins 557 are positioned such that the tops of the lift pins just fillthe holes in the lift pad 430, which is an appropriate position duringchamber pre-coat, when pre-coat deposition occurs, and no wafer is onthe lift pad and pedestal configuration.

In particular, pre-coat and undercoat layers of the film are depositedin the process chamber before wafers are processed. This pre-coat and/orundercoat film may also coat the carrier rings, when included in thelift pad and pedestal configuration, which come into contact with thewafer. It is believed that applying a pre-coat to the chamber and liftpad and pedestal configuration (e.g., contact support structures, suchas MCAs), and optional carrier ring with a pre-coat film similar to thefilm that will be formed over the wafer during processing improves filmformation over the wafer. As such, a pre-coat film is formed before thewafer is introduced over the lift pad and pedestal configuration. Inaddition, the pre-coat, as well as any further undercoatings, of thewafer processing environment serve, in combination, for improved waferfilm uniformity. For example, a typical undercoat thickness may beapproximately 3 microns, and a pre-coat thickness is approximately 0.5microns.

FIG. 9B also shows the lift pad and pedestal configuration 400 in theprocess position, wherein one or more films may be deposited duringwafer processing (e.g., PECVD and ALD processes) in single-station andmulti-station systems. In particular, pedestal 140′ is at a level withinthe corresponding chamber indicated by line 903. As shown, the pedestal140′ is near its topmost position or level in the chamber. It isimportant to note that the process position may be defined at anyposition and/or level within the chamber, depending on the chamberand/or processes implemented, and is not limited to the level indicatedby line 903. As shown, the lift pad 430 rests upon the pedestal 140′, aspreviously described. In addition, the lift pins 557 are positioned suchthat the tops of the lift pins are within the body of the pedestal 140′,such that the tops may also be positioned anywhere within the pedestal140′ or lift pad 430. In addition, the lift pad 430 is in a firstangular orientation in relation to the pedestal 140′.

FIG. 9B also shows the lift pad and pedestal configuration 400 in therotation position, wherein the pedestal is at an upwards position. Inone embodiment, the bottom of pedestal 140′ is at a topmost level withinthe corresponding chamber indicated by line 904. The lift pad 430 isseparated from the pedestal 140′ by a process rotation displacement 940(e.g., on the order of 1 mm). In one embodiment, a coupled mechanismraises the lift pad 430 when the pedestal 140′ nears the top of itstravel, such that the lift pad is separated from the pedestal topsurface by the rotation displacement 940. In particular, as the pedestal140′ reaches the top of its travel, over a certain distance “d” traveledby the pedestal 140′, the lift pad 430 moves by a greater distance thatmay be a factor of “d.” For example, as pedestal 140′ reaches the top ofits travel, the lift pad 430 separates from the pedestal 140′ byrotation displacement 940 that is double the distance “d.” Thereafter,the lift pad 430 may be rotated from a first angular orientation to asecond angular orientation, with respect to the pedestal 140′, forexample. Thereafter, the lift pad and pedestal configuration 400 may bereturned to the process position for additional processing cycles, or tothe delivery position for wafer delivery.

FIG. 9C is a diagram illustrating the orientation of a lift pad 430 withrespect to a pedestal 140′ in a lift pad and pedestal configuration 400,wherein the lift pad is approximately sized to a wafer, during a firstprocess sequence, a rotation sequence, and a second process sequence, inaccordance with one embodiment of the present disclosure. In particular,FIG. 9C illustrates the relative orientations (e.g., with respect toeach other and/or with respect to a coordinate system 950 within achamber) of the lift pad 430 and the pedestal 140′ while the lift padand pedestal configuration 400 is in a process position for a firstnumber of processing cycles, while the configuration 400 is in arotation position, and while the configuration 400 is in a processposition for a second number of processing cycles.

As shown, during the first number of processing cycles, the lift pad andpedestal configuration 400 is in the process position. In particular,both the lift pad 430 and the pedestal 140′ have an angular orientationof 0 degrees with respect to coordinate system 950 in the chamber. Also,the lift pad 430 has a first angular orientation of 0 degrees withrespect to the pedestal 140′ (i.e., the pedestal 140′ provides thecoordinate system).

In addition, FIG. 9C illustrates the rotation of the lift pad 430 withrespect to the pedestal 140′, when the lift pad and pedestalconfiguration 400 are in the rotation position. In particular, thepedestal 140′ remains static with an angular orientation of 0 degrees(e.g., with reference to the coordinate system 950), while the lift pad430 is rotating from an angular orientation of 0 degrees to 180 degrees.That is, the pedestal 140′ does not rotate. As shown, the lift pad 430is midway through its orientation at an angular orientation of 71degrees.

Further, during the second number of processing cycles, the lift pad andpedestal configuration 400 is again in the process position. However,because of the rotation of the lift pad, the pedestal 140′ still has anangular orientation of 0 degrees with respect to coordinate system 950in the chamber, and the lift pad has an angular orientation of 180degrees. Put another way, when processing the first number of cycles,the lift pad 430 has an angular orientation of 0 degrees with referenceto the pedestal 140′, and when processing the second number of cycles,the lift pad 430 after rotation has an angular orientation of 180degrees, for example, with reference to pedestal 140′.

FIGS. 10A-10C are diagrams illustrating the motion sequence of a liftpad and pedestal configuration, wherein the lift pad is smaller than awafer, and includes the rotation of the wafer without rotation of thepedestal within a process chamber during processing, whichadvantageously filters out both chamber and pedestal asymmetries, inaccordance with one embodiment of the present disclosure. Moreparticularly, FIG. 10B shows a lift pad and pedestal configuration 600,first introduced in FIGS. 6 and 7A-7B. FIG. 10C shows a lift pad andpedestal configuration 600′, first introduced in FIG. 7C, andadditionally includes a lift pin assembly.

In particular, FIG. 10A shows the lift pad and pedestal configuration600, that includes a pedestal 140″ and lift pad 630. The lift pad andpedestal configuration 600 is configured such that the lift pad 630provides the lifting action, and eliminates the need for a lift pinassembly. Specifically, in the delivery position, the lift pad andpedestal configuration 600 is configured such that the pedestal 140″ isat a bottomwards position with the lift pad 630 separated from thepedestal 140″ by a displacement large enough for entry of anend-effector arm. FIG. 10A also shows the lift pad and pedestalconfiguration 600 in the process position, wherein one or more films maybe deposited (e.g., PECVD and ALD processes) during wafer processing insingle-station and multi-station systems. FIG. 10A also shows the liftpad and pedestal configuration 600 in the rotation position, wherein thepedestal 140″ is at an upwards position (e.g., topmost upwardsposition), and the lift pad 630 is separated from the pedestal 140″ by aprocess rotation displacement (e.g., 1 mm).

FIG. 10B provides more details to FIG. 10A, and illustrate the motionsequence of the lift pad and pedestal configuration 600, wherein thelift pad is smaller than a wafer, and includes the rotation of the waferwithout rotation of the pedestal within a process chamber duringprocessing, which advantageously filters out both chamber and pedestalasymmetries, in accordance with one embodiment of the presentdisclosure.

In the delivery position of the lift pad and pedestal configuration, thebottom of pedestal 140″ is at a level within the corresponding chamberindicated by line 901. In particular, the pedestal 140″ is at itsbottommost level, in one embodiment. In one embodiment, the deliveryposition is lower than the pre-coat position indicated by line 902, aswell as the process position indicated by line 903, and the rotationposition indicated by line 904. As shown, the lift pad 630 is separatedfrom the lift pad 140″ by a displacement 969 sufficient to allow an armof an end-effector to deliver (place onto the lift pad 630, or removewafer from the lift pad 630), as is shown in FIG. 10B. In oneembodiment, a coupled mechanism raises the lift pad 630 when thepedestal 140″ nears the bottom of its travel, such that the lift pad 630is separated from the pedestal top surface by the displacement 969.

FIG. 10B also shows the lift pad and pedestal configuration 600 in thepre-coat position, wherein pre-coat and undercoat layers of the film aredeposited in the process chamber before wafers are processed. In thepre-coat position, the bottom of the pedestal 140″ is at a level withina corresponding chamber indicated by line 902, for example. The pre-coatposition may be defined at any position within the chamber, and is notlimited to the level indicated by line 902. As shown, the lift pad 630rests upon the pedestal 140″, as previously described.

In the process position of the lift pad and pedestal configuration 600,the bottom of pedestal 140″ is at a level within the correspondingchamber indicated by line 903. In one embodiment, the pedestal 140″ isnear its topmost position or level in the chamber, though the processposition may be at any level within the chamber depending on the chamberand/or processes implemented, as previously described. As shown, thelift pad 630 rests upon the pedestal 140″. In addition, the lift pad 630is in a first angular orientation in relation to the pedestal 140″.

In the rotation position of the lift pad and pedestal configuration 600,the bottom of pedestal 140″ is at a topmost level within thecorresponding chamber indicated by line 904, in one embodiment. The liftpad 630 is separated from the pedestal 140″ by a process rotationdisplacement 1040 (e.g., on the order of 1 mm). In one embodiment, acoupled mechanism raises the lift pad 630 via the pad shaft 560′ whenthe pedestal 140″ nears the top of its travel, such that the lift pad630 is separated from the pedestal top surface by the rotationdisplacement 1040. In one embodiment, a coupled mechanism raises thelift pad 630 when the pedestal 140″ nears the top of its travel, suchthat the lift pad 630 is separated from the pedestal top surface by therotation displacement 1040. For example, as the pedestal 140″ reachesthe top of its travel, over a certain distance “f” traveled by pedestal140″, the lift pad 630 moves by a greater distance that may be a factorof “f” (e.g., two times “f”). Thereafter, the lift pad 630 may berotated from a first angular orientation to a second angular orientation(e.g., with respect to pedestal 140″), and then either returned to theprocess position for additional processing cycles, or returned to thedelivery position for wafer delivery.

FIG. 10C provides more details to FIG. 10A, and illustrate the motionsequence of the lift pad and pedestal configuration 600′ including alift pin assembly, wherein the lift pad 630 is smaller than a wafer, andincludes the rotation of the wafer without rotation of the pedestal140′″ within a process chamber during processing, which advantageouslyfilters out both chamber and pedestal asymmetries, in accordance withone embodiment of the present disclosure. As previously described, liftpad and pedestal configuration 600′ includes a lift pad 630, pedestal140′″ and lift pin assembly.

In the delivery position of the lift pad and pedestal configuration600′, the bottom of pedestal 140′″ is at a level within thecorresponding chamber indicated by line 901. In particular, the pedestal140′″ is at its bottommost level, in one embodiment. In one embodiment,the delivery position is lower than the pre-coat position indicated byline 902, as well as the process position indicated by line 903, and therotation position indicated by line 904. As shown, the lift pad 630rests upon pedestal 140′″, as previously described. In addition, thelift pins 557′ extend beyond the top surface of the pedestal 140′″ andlift pad 630, in a position to receive a wafer that is delivered by anarm of an end-effector, or for removal of a wafer by the end-effector,for example.

FIG. 10C also shows the lift pad and pedestal configuration 600′ in thepre-coat position, wherein pre-coat and undercoat layers of the film aredeposited in the process chamber before wafers are processed. In thepre-coat position, the bottom of the pedestal 140′″ is at a level withina corresponding chamber indicated by line 902, for example. The pre-coatposition may be defined at any position within the chamber, and is notlimited to the level indicated by line 902. As shown, the lift pad 630rests upon the pedestal 140′″, as previously described. In addition, thelift pins 557′ are positioned such that the tops of the lift pins justfill the holes in the lift pad 630, which is an appropriate positionduring chamber pre-coat, when pre-coat deposition occurs, and no waferis on the lift pad and pedestal configuration.

In the process position of the lift pad and pedestal configuration 600′,the bottom of pedestal 140′″ is at a level within the correspondingchamber indicated by line 903. As shown, the pedestal 140′″ is near itstopmost position or level in the chamber, though the process positionmay be at any level within the chamber, as previously described. Asshown, the lift pad 630 rests upon the pedestal 140′″, as previouslydescribed. In addition, the lift pins 557′ are positioned such that thetops of the lift pins are within the pedestal 140′″, though the tops mayalso be positioned anywhere within the pedestal 140′″.

In the rotation position of the lift pad and pedestal configuration600′, the bottom of pedestal 140′″ is at a topmost level within thecorresponding chamber indicated by line 904, in one embodiment. The liftpad 630 is separated from the pedestal 140′″ by a process rotationdisplacement 1040 (e.g., on the order of 1 mm). In one embodiment, acoupled mechanism raises the lift pad 630 via the pad shaft 560′ whenthe pedestal 140″′ nears the top of its travel, such that the lift pad630 is separated from the pedestal top surface by the rotationdisplacement 1040. In one embodiment, a coupled mechanism raises thelift pad 630 when the pedestal 140′″ nears the top of its travel, suchthat the lift pad 630 is separated from the pedestal top surface by therotation displacement 1040. For example, as the pedestal 140′″ reachesthe top of its travel, over a certain distance “f” traveled by pedestal140″′, the lift pad 630 moves by a greater distance that may be a factorof “f” (e.g., two times “f”). Thereafter, the lift pad 630 may berotated from a first angular orientation to a second angular orientation(e.g., with respect to pedestal 140′″), and then either returned to theprocess position for additional processing cycles, or returned to thedelivery position for wafer delivery.

FIG. 10D is a diagram illustrating the orientation of a lift pad 630with respect to a pedestal 140″ in a lift pad and pedestal configuration600, or with respect to a pedestal 140′″ in a lift pad and pedestalconfiguration 600′, wherein the lift pad 630 is smaller than a wafer,during a first process sequence, a rotation sequence, and a secondprocess sequence, in accordance with one embodiment of the presentdisclosure. In particular, FIG. 10D illustrates the relativeorientations (e.g., with respect to each other and/or with respect to acoordinate system 1050 within a chamber) of the lift pad 630 and thepedestal 140″/pedestal 140′″ while the lift pad and pedestalconfiguration 600/600′ is in a process position for a first number ofprocessing cycles, while in a rotation position, or a process positionfor a second number of processing cycles.

As shown, during the first number of processing cycles, the lift pad andpedestal configuration 600/600′ is in the process position. Inparticular, both the lift pad 630 and the pedestal 140″/140′″ have anangular orientation of 0 degrees with respect to coordinate system 1050in the chamber. Also, the lift pad 630 has a first angular orientationof 0 degrees with respect to the pedestal 140″/140′″ (i.e., the pedestal140″/140′″ provides the coordinate system).

In addition, FIG. 10D illustrates the rotation of the lift pad 630 withrespect to the pedestal 140″/140′″, when the lift pad and pedestalconfiguration 600/600′ are in the rotation position. In particular, thepedestal 140″/140′″ remains static with an angular orientation of 0degrees (e.g., with reference to the coordinate system 1050), while thelift pad 630 is rotating from an angular orientation of 0 degrees to 180degrees. That is, the pedestals 140″ and 140′″ do not rotate. As shown,the lift pad 630 is midway through its orientation at an angularorientation of 71 degrees.

Further, during the second number of processing cycles, the lift pad andpedestal configuration 600/600′ is again in the process position.However, because of the rotation of the lift pad, the pedestal140″/140′″ still has an angular orientation of 0 degrees with respect tocoordinate system 1050 in the chamber, and the lift pad has an angularorientation of 180 degrees. Put another way, when processing the firstnumber of cycles, the lift pad 630 has an angular orientation of 0degrees with reference to the pedestal 140″/140′″, and when processingthe second number of cycles, the lift pad 630 after rotation has anangular orientation of 180 degrees, for example, with reference topedestal 140″/140′″.

FIG. 11 shows a control module 1100 for controlling the systemsdescribed above. In one embodiment, the control module 110 of FIG. 1 mayinclude some of the example components of control module 1100. Forinstance, the control module 1100 may include a processor, memory andone or more interfaces. The control module 1100 may be employed tocontrol devices in the system based in part on sensed values. Forexample only, the control module 1100 may control one or more of valves1102, filter heaters 1104, pumps 1106, and other devices 1108 based onthe sensed values and other control parameters. The control module 1100receives the sensed values from, for example only, pressure manometers1110, flow meters 1112, temperature sensors 1114, and/or other sensors1116. The control module 1100 may also be employed to control processconditions during precursor delivery and deposition of the film. Thecontrol module 1100 will typically include one or more memory devicesand one or more processors.

The control module 1100 may control activities of the precursor deliverysystem and deposition apparatus. The control module 1100 executescomputer programs including sets of instructions for controlling processtiming, delivery system temperature, and pressure differentials acrossthe filters, valve positions, mixture of gases, chamber pressure,chamber temperature, substrate temperature, RF power levels, substratechuck or pedestal position, and other parameters of a particularprocess. The control module 1100 may also monitor the pressuredifferential and automatically switch vapor precursor delivery from oneor more paths to one or more other paths. Other computer programs storedon memory devices associated with the control module 1100 may beemployed in some embodiments.

Typically there will be a user interface associated with the controlmodule 1100. The user interface may include a display 1118 (e.g., adisplay screen and/or graphical software displays of the apparatusand/or process conditions), and user input devices 1120 such as pointingdevices, keyboards, touch screens, microphones, etc.

Computer programs for controlling delivery of precursor, deposition andother processes in a process sequence can be written in any conventionalcomputer readable programming language: for example, assembly language,C, C++, Pascal, Fortran or others. Compiled object code or script isexecuted by the processor to perform the tasks identified in theprogram.

The control module parameters relate to process conditions such as, forexample, filter pressure differentials, process gas composition and flowrates, temperature, pressure, plasma conditions such as RF power levelsand the low frequency RF frequency, cooling gas pressure, and chamberwall temperature.

The system software may be designed or configured in many differentways. For example, various chamber component subroutines or controlobjects may be written to control operation of the chamber componentsnecessary to carry out the inventive deposition processes. Examples ofprograms or sections of programs for this purpose include substratepositioning code, process gas control code, pressure control code,heater control code, and plasma control code.

A substrate positioning program may include program code for controllingchamber components that are used to load the substrate onto a pedestalor chuck and to control the spacing between the substrate and otherparts of the chamber such as a gas inlet and/or target. A process gascontrol program may include code for controlling gas composition andflow rates and optionally for flowing gas into the chamber prior todeposition in order to stabilize the pressure in the chamber. A filtermonitoring program includes code comparing the measured differential(s)to predetermined value(s) and/or code for switching paths. A pressurecontrol program may include code for controlling the pressure in thechamber by regulating, e.g., a throttle valve in the exhaust system ofthe chamber. A heater control program may include code for controllingthe current to heating units for heating components in the precursordelivery system, the substrate and/or other portions of the system.Alternatively, the heater control program may control delivery of a heattransfer gas such as helium to the substrate chuck.

Examples of sensors that may be monitored during deposition include, butare not limited to, mass flow control modules, pressure sensors such asthe pressure manometers 1110, and thermocouples located in deliverysystem, the pedestal or chuck (e.g., the temperature sensors 1114/607).Appropriately programmed feedback and control algorithms may be usedwith data from these sensors to maintain desired process conditions. Theforegoing describes implementation of embodiments of the disclosure in asingle or multi-chamber semiconductor processing tool.

In some implementations, a controller is part of a system, which may bepart of the above-described examples. Such systems can comprisesemiconductor processing equipment, including a processing tool ortools, chamber or chambers, a platform or platforms for processing,and/or specific processing components (a substrate pedestal, a gas flowsystem, etc.). These systems may be integrated with electronics forcontrolling their operation before, during, and after processing of asemiconductor wafer or substrate. The electronics may be referred to asthe “controller,” which may control various components or subparts ofthe system or systems. The controller, depending on the processingrequirements and/or the type of system, may be programmed to control anyof the processes disclosed herein, including the delivery of processinggases, temperature settings (e.g., heating and/or cooling), pressuresettings, vacuum settings, power settings, radio frequency (RF)generator settings, RF matching circuit settings, frequency settings,flow rate settings, fluid delivery settings, positional and operationsettings, substrate transfers into and out of a tool and other transfertools and/or load locks connected to or interfaced with a specificsystem.

Broadly speaking, the controller may be defined as electronics havingvarious integrated circuits, logic, memory, and/or software that receiveinstructions, issue instructions, control operation, enable cleaningoperations, enable endpoint measurements, and the like. The integratedcircuits may include chips in the form of firmware that store programinstructions, digital signal processors (DSPs), chips defined asapplication specific integrated circuits (ASICs), and/or one or moremicroprocessors, or microcontrollers that execute program instructions(e.g., software). Program instructions may be instructions communicatedto the controller in the form of various individual settings (or programfiles), defining operational parameters for carrying out a particularprocess on or for a semiconductor substrate or to a system. Theoperational parameters may, in some embodiments, be part of a recipedefined by process engineers to accomplish one or more processing stepsduring the fabrication of one or more layers, materials, metals, oxides,silicon, silicon dioxide, surfaces, circuits, and/or dies of a wafer.

The controller, in some implementations, may be a part of or coupled toa computer that is integrated with, coupled to the system, otherwisenetworked to the system, or a combination thereof. For example, thecontroller may be in the “cloud” of all or a part of a fab host computersystem, which can allow for remote access of the substrate processing.The computer may enable remote access to the system to monitor currentprogress of fabrication operations, examine a history of pastfabrication operations, examine trends or performance metrics from aplurality of fabrication operations, to change parameters of currentprocessing, to set processing steps to follow a current processing, orto start a new process. In some examples, a remote computer (e.g., aserver) can provide process recipes to a system over a network, whichmay include a local network or the Internet.

The remote computer may include a user interface that enables entry orprogramming of parameters and/or settings, which are then communicatedto the system from the remote computer. In some examples, the controllerreceives instructions in the form of data, which specify parameters foreach of the processing steps to be performed during one or moreoperations. It should be understood that the parameters may be specificto the type of process to be performed and the type of tool that thecontroller is configured to interface with or control. Thus as describedabove, the controller may be distributed, such as by comprising one ormore discrete controllers that are networked together and workingtowards a common purpose, such as the processes and controls describedherein. An example of a distributed controller for such purposes wouldbe one or more integrated circuits on a chamber in communication withone or more integrated circuits located remotely (such as at theplatform level or as part of a remote computer) that combine to controla process on the chamber.

Without limitation, example systems may include a plasma etch chamber ormodule, a deposition chamber or module, a spin-rinse chamber or module,a metal plating chamber or module, a clean chamber or module, a beveledge etch chamber or module, a physical vapor deposition (PVD) chamberor module, a chemical vapor deposition (CVD) chamber or module, anatomic layer deposition (ALD) chamber or module, an atomic layer etch(ALE) chamber or module, an ion implantation chamber or module, a trackchamber or module, and any other semiconductor processing systems thatmay be associated or used in the fabrication and/or manufacturing ofsemiconductor wafers.

As noted above, depending on the process step or steps to be performedby the tool, the controller might communicate with one or more of othertool circuits or modules, other tool components, cluster tools, othertool interfaces, adjacent tools, neighboring tools, tools locatedthroughout a factory, a main computer, another controller, or tools usedin material transport that bring containers of wafers to and from toollocations and/or load ports in a semiconductor manufacturing factory.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

Although the foregoing embodiments have been described in some detailfor purposes of clarity of understanding, it will be apparent thatcertain changes and modifications can be practiced within the scope ofthe appended claims. Accordingly, the present embodiments are to beconsidered as illustrative and not restrictive, and the embodiments arenot to be limited to the details given herein, but may be modifiedwithin their scope and equivalents of the claims.

What is claimed is:
 1. An assembly for use in a process chamber fordepositing a film on a wafer, comprising: a pedestal having a pedestaltop surface extending from a central axis; an actuator configured forcontrolling movement of the pedestal; a central shaft extending betweenthe actuator and the pedestal, the central shaft configured to move thepedestal along the central axis; a lift pad having a pad top surfaceextending from the central axis to a pad diameter and a pad bottomsurface configured to rest upon the pedestal top surface, the pad topsurface configured to support a wafer when placed thereon; and a padshaft extending between the actuator and the lift pad, the actuatorconfigured for controlling movement of the lift pad, the pad shaftconfigured to separate the lift pad from the pedestal, the pad shaftpositioned within the central shaft; wherein the lift pad is configuredto move up relative to the pedestal top surface along the central axiswhen the pedestal is in an upwards position, such that the lift pad isseparated from the pedestal top surface by a process rotationdisplacement; wherein the lift pad is configured to rotate relative tothe pedestal top surface when separated from the pedestal between atleast a first angular orientation and a second angular orientation. 2.The assembly of claim 1, further comprising: a plurality of pad supportsdisposed on the pedestal top surface, the pad supports configured tosupport the lift pad at a pad support level above the pedestal topsurface.
 3. The assembly of claim 2, wherein a pad support iselectrically conductive.
 4. The assembly of claim 2, wherein when thepedestal and lift pad are in a process position, the lift pad is restingupon the plurality of pad supports.
 5. The assembly of claim 1, whereinthe lift pad further comprises: an electrostatic chuck (ESC) assemblydisposed below the pad top surface.
 6. The assembly of claim 1, whereina diameter of the pad top surface is approximately sized to a waferdiameter.
 7. The assembly of claim 6, wherein the diameter of the padtop surface is sized to accommodate a carrier ring.
 8. The assembly ofclaim 1, wherein a diameter of the pad top surface is smaller than awafer diameter.
 9. The assembly of claim 1, further comprising: a liftpin assembly including a plurality of lift pins extending through aplurality of pedestal shafts configured within the pedestal.
 10. Theassembly of claim 9, wherein the plurality of lift pins is configured toextend through a plurality of lift pad shafts configured within the liftpad.
 11. The assembly of claim 9, wherein when the pedestal and lift padare in a pre-coat position, the lift pad is resting upon the pedestaland the plurality of lift pins is positioned to extend up to thepedestal top surface.
 12. The assembly of claim 1, wherein the lift padis configured to move with the pedestal.
 13. The assembly of claim 1,further comprising: a flexible coupler positioned within the pad shaftand configured to position the lift pad uniformly above the pedestal.14. An assembly for use in a process chamber for depositing a film on awafer, comprising: a pedestal having a pedestal top surface extendingfrom a central axis of the pedestal, the pedestal top surface configuredto support a wafer when placed thereon; a recess centered in thepedestal top surface extending from the central axis, the recess havinga recess height, the recess having a recess bottom surface; an actuatorconfigured for controlling movement of the pedestal; a central shaftextending between the actuator and the pedestal, the central shaftconfigured to move the pedestal along the central axis; a lift padhaving a pad top surface extending from the central axis to a paddiameter, the lift pad configured rest upon the recess bottom surfacewhen situated within the recess, wherein the recess is configured toreceive the lift pad; a pad shaft extending between the actuator and thelift pad, the actuator configured for controlling movement of the liftpad, the pad shaft configured to separate the lift pad from thepedestal, the pad shaft positioned within the central shaft; wherein thelift pad is configured to move up relative to the pedestal top surfacealong the central axis when the pedestal is in an upwards position, suchthat the lift pad is separated from the pedestal top surface by aprocess rotation displacement; wherein the lift pad is configured torotate relative to the pedestal top surface when separated from thepedestal between at least a first angular orientation and a secondangular orientation.
 15. The assembly of claim 14, further comprising: aplurality of pad supports disposed on the recess bottom surface, the padsupports configured to support the lift pad at a pad support level abovethe recess bottom surface.
 16. The assembly of claim 14, furthercomprising: a plurality of wafer supports disposed on the pedestal topsurface, the wafer supports configured to support a wafer when placedthereon at a wafer support level above the pedestal top surface.
 17. Theassembly of claim 16, wherein the pad top surface is under the wafersupport level when the lift pad rests upon the recess bottom surface.18. The assembly of claim 16, further comprising: a raised rim disposedon an outer edge of the pedestal top surface, the raised rim configuredfor blocking lateral movement of a wafer that is placed on the pedestal.19. The assembly of claim 14, wherein the lift pad is configured to moveup relative to the pedestal top surface when the pedestal is in abottommost downwards position, such that the lift pad is separated fromthe pedestal top surface by a displacement large enough for entry of anend-effector arm.